The invention is directed to improvements in fuel injection pumps whose supply pressure is controllable by a valve in accordance with at least one operating characteristic of the engine.
In a fuel injection pump of this type, disclosed in F.R.G. Pat. No. 19 13 808, the valve, in the form of an electrically controllable valve, is disposed in the fuel supply line leading from the fuel supply chamber of the pump to the pump work chamber. The valve is a magnetic valve, the closing member of which is located in the closing position when the coil is not excited. When the fuel injection pump is in operation, the magnetic valve is moved into its opening position by an rpm signal and is kept there until such time as the rpm exceeds a predetermined value. When this value is exceeded the result is an interruption of the supply of electric current to the magnetic valve, so that the fuel supply line is closed by the closing member of the magnetic valve. The rpm threshold value is detected via fuses located in the current supply circuit of the magnetic valve, which via a response value limit the rpm-dependent current load on the magnetic valve. The control provided in the known apparatus serves to shut off the engine if the maximum rpm is exceeded.